The present invention relates generally to charging devices for use in electrostatographic devices and more particularly to corona-charging devices for use in such machines, which provide for accurate location of such devices.
Generally, the process of electrostatographic copying is executed by exposing a light image of an original document to a substantially uniformly charged photoreceptor member. Exposing the charged photoreceptor member to a light image selectively discharges the photoconductive surface thereof to create an electrostatic latent image of the original document on the photoreceptor member. The electrostatic latent image is subsequently developed into a visible image by a process in which charged developing material is deposited onto the photoconductive surface of the photoreceptor such that the developing material is selectively attracted to the image areas thereon. The developing material is then transferred from the photoreceptor member to a copy sheet on which the toner image may be permanently affixed to provide a reproduction of the original document. In a final step, the photoconductive surface of the photoreceptor member is cleaned to remove any residual developing material therefrom in preparation for successive imaging cycles.
The described process is well known and is useful for light lens copying from the original as well as the printing of documents from electronically generated or stored originals. Analogous processes also exist in other electrostatographic applications such as, for example, digital printing applications where latent images are generated by a modulated laser beam or LED printhead, or ionographic printing and reproduction processes in which charges are selectively deposited on a charge retentive surface in accordance with an image stored in electronic form.
In electrostatographic applications, it is common practice to use corona-generating devices for providing electrostatic fields to drive various machine operations. Such corona devices are primarily used to deposit charge on the photoreceptor member prior to exposure to the light image for subsequently enabling toner transfer thereto. In addition, corona devices are used in the transfer of an electrostatic toner image from a photoreceptor to a transfer substrate, in tacking and detacking paper to or from the imaging member by applying a neutralizing charge to the paper, and, generally in conditioning the imaging surface prior to, during and after toner is deposited thereon to improve the quality of the xerographic output copy.
In use, corona-generating wires are noted for the ability to produce reasonably uniform charge on a surface to be charged. However, in order to do so they are required to be positioned in accurate spacing from the surface to be charged. When positioned adjacent a roller, such as a transfer roller, the position of the photoconductive belt may be accurately controlled relative to the transfer roller. However, separate adjustment of the charger relative to the belt requires either expensive alignment structure for the charger or a service representative's time to accurately position the charger. It is an object of the invention to provide a device and method which facilitates accurate placement of the corona charger device.